1. Erawanm Waterfalls
These famous 7-tiered waterfalls are located in the Erawan National Park which is 65 km from Kanchanaburi on Highway 3199. The falls are situated amongst rough jungle and are truly one of the most beautiful falls in Asia. You can follow a trekking path inside the national park or stay overnight.
2. Sai Yok National Park
The main attractions are Sai Yok Yai and Sai Yok Lek waterfalls, both of which emerge as streams out of the forest before plummeting eight to 10 metres into the River Kwai. A suspension footbridge has been set up near Sai Yok Yai, which takes you across the river to a viewing point. You'll need to pay a longtail boat 300 baht to take you the half-kilometre down river to see Sai Yok Lek, oddly the slightly larger of the two (lek means "small" while yai means "big" in Thai).
3. Sri Nakarin Dam
Kanchanaburi produces 41 percent of the electrical energy used in Thailand. It is produced by freshwater resources mainly from Sri Nakarin and Khao Lam Dam. Sri Nakarin Dam is about 3 km north of the Erawan Falls and about 68 km from town. The Sri Nakarin Lake offers fishing, luxurious raft hotels, weekend boat tours and watersports. It is surrounded by the Sri Nakarin National Park.